Sediments constitute the benthic environment, and play an important role in marine ecosystems. Various chemicals persist in sediments and can affect the benthic organisms. However, it has generally been difficult to identify specific toxicants that critically the effects in organisms. In the present study, we evaluated the toxicities of sediments collected from several sites in Japanese coastal areas, using fish embryos. As a result, some sediments induced embryo mortality and malformation in hatching larvae. We explored several approaches to facilitate the identification of causative chemicals based on biological responses in fish embryos. Hydrophobic extracts added into test water obtained from most sediments induced effects such as mortality and malformations in embryos. However, because hydrophilic extracts also affected embryos for a few sites, we could not distinguish the remarkable signatures based solely on the extract exposures. In addition, receptor activation by ligand-binding chemicals derived from these extracts―implicating xenobiotic metabolism, vitamin metabolism, and other pathways―was examined using the corresponding nuclear receptor target genes, and some genes changed at least partially with their effect-related factors. The approach of obtaining extracts followed by gene analysis, owing to its broad applicability, was suggested to be a potentially effective method for picking up candidate causative toxicants in sediments in the future.

In the European Union, a revised version of the “Guideline on Environmental Risk Assessment of Medicinal Products for Human Use” (EMEA/CHMP/SWP/4447/00) came into effect in September, 2024. This review explains the revised contents of the Guideline, summarizes points to note when conducting an environmental risk assessment, and proposes a useful project model for the pharmaceutical industry.